PSI - Issue 64

Manuel Boccolini et al. / Procedia Structural Integrity 64 (2024) 2206–2213 Manuel Boccolini/ Structural Integrity Procedia 00 (2024) 000 – 000

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1. Introduction Integrated monitoring of infrastructures (bridges, dams, etc.), boosted by recent tragic collapses, is becoming increasingly common as a tool for continuous performance check during operation and in the event of exceptional actions of either natural of anthropic genesis (earthquakes, heavy rainfalls, strong windstorms, collisions, blasts, etc.). However, monitoring techniques devoted to the overall behavior of building bodies are still nowadays very uncommon, despite devices, software and hardware computer tools for data acquisition, processing, and display have remarkably evolved. This makes the post-event field surveys and damage mapping of building structures extremely difficult, as well as retrofit intervention timespans very long, with negative reflection over the resilience of the whole built heritage. The development of integrated monitoring systems to detect multiple parameters is however currently experiencing a boost by a growing focus on strategies aimed at environmental sustainability policies and the presence of international certification bodies (including the U.S. Green Building Council, the Building Research Establishment and the International WELL Building Institute), which use collected data to assign a sustainability rating to buildings. These parameters include energy surveys for consumption control and optimization or the measurement of energy produced locally from renewable sources, environmental measurements for the health of occupants through monitoring of the presence of pollutants, and engineering parameters providing information on the structural durability, robustness, and resilience of buildings. Manini Prefabbricati SpA, among the leading EU companies in the precast construction sector, patented the "Manini Connect" system in 2017, consisting in an integrated and scalable monitoring system designed and developed following the guidelines of Industry 4.0 and the Internet of Things (Coviello et al. 2020). The rationale is to offer a new after-sales service of continuous active control of the building, monitoring specific performances both during operation and in case of exceptional events. The development team has continuously worked over the last years to make the Manini Connect system increasingly efficient, optimizing and integrating new related functionalities, including the urgent need to implement environmentally sustainable development policies. Currently, the system includes integrated continuous monitoring of structures, energy, and environment, performed via real-time continuous acquisition. So far, the system has been installed in dozens of building structures, mainly industrial and commercial facilities. The present paper provides a brief technical survey of the Manini Connect system and reports some applications. 2. Structural Monitoring Structural monitoring is conducted using two various sensors, the physical supports of which are embedded, along with wiring conduits, inside the structural elements during the concrete casting phase. This ensures that the system is perfectly coupled with the element, and the columns containing it are referred to as "smart columns" (Fig. 1). Additionally, an external environmental station is typically installed over the roof (Fig. 2). Its dimensions allow to easily position it even in curved roofs such as those employing the Ondal system with wing-shaped roof elements (Dal Lago 2017). The station contains, in addition to another series of sensors, a Programmable Logic Controller (PLC), enabling data transmission to a dedicated platform constantly monitored by the Control Center at Manini Prefabbricati S.p.A. An early warning alert activates upon exceeding one of the thresholds set for each recorded parameter. 2.1. Integrated Sensor System Each smart column features a minimum of three compartments designated to accommodate sensors, positioned as follows: • an accelerometer positioned in the bottom box of the column to monitor accelerations generated by exceptional events such as earthquakes (Dal Lago 2021, Bosio et al. 2023) or impacts/blasts (input towards the structure); • an accelerometer positioned in the top box of the column and eventually in the intermediate box(es) to measure accelerations near the floor resulting, for example, from oscillations caused by a seismic event, or wind-induced vortex shedding, or mechanical vibrations induced by machines installed over the floor, or human-induced vibrations over slender slabs (Dal Lago et al. 2022);